The present invention relates to materials for packaging nicotine-containing products.
For many years tobacco smoking has been one of the major health problems throughout the world. Smoking is now recognized as the main cause for e.g. high blood pressure and lung cancer. However, because of the addictive nature of nicotine it is utterly difficult for heavy smokers to completely stop smoking. An acceptable alternative to smoking has been to provide nicotine in a form or manner other than by smoking, e.g. as a chewing gum containing nicotine as an active ingredient, see e.g. U.S. Pat. No. 3,845,217. Other products used as substitutes for smoking are tablets containing nicotine, see e.g. U.S. Pat. No. 5,543,424, devices for allowing nicotine to be inhaled through an elongated tube, see e.g. U.S. Pat. No. 5,501,236, nicotine containing nasal sprays, see e.g. U.S. Pat. No. 5,656,255, patches for administering nicotine transdermally, see e.g. U.S. Pat. No. 4,915,950, etc.
The primary requirement when packaging drugs and food is the demand that the package must protect the product against penetration of moisture and oxygen from the environment. Very seldom the product itself constitutes any problems. Nicotine, on the other hand, is very aggressive towards its environment and migrates through most known materials. It is also very hygroscopic and therefore sensitive to moisture and when exposed to oxygen or air the nicotine turns brown. Because of the toxicity of nicotine and because the expected shelf-life for nicotine containing products is as long as up to two years, commonly used materials within the package industry, e.g. polypropylene, polyethylene and polyvinyl chloride therefore cannot be used for nicotine containing products.
A known polymer which fulfills the requirements of oxygen, water and nicotine impermeability is commercially available under the trademark Barex(copyright), being a copolymer made of acrylonitrile and methylmetacrylate and grafted to nitrile rubber on the main chain. Due to the copolymerization with methylmethacrylate the polymer becomes softer and is possible to process. Barex(copyright) is available with different amounts of nitrile rubber, is amorphous and is a glass polymer at room temperature.
The temperature range within which Barex(copyright) may be processed is, however, very narrow rendering the polymer difficult to process resulting in a large amount of discarded material. This is partly due to Barex(copyright) having a temperature dependent elasticity. Today, Barex(copyright) is also associated with a high price.
The use of Barex(copyright) in a nicotine impermeable container is disclosed in U.S. Pat. No. 5,501,236.
It is therefore an object of the present invention to provide an alternative material to Barex(copyright), which exhibits favorable characteristics of oxygen, water and nicotine impermeability, but which does not suffer from the above-mentioned drawbacks. According to the invention it is therefore suggested an alternative nicotine impermeable packaging material for a nicotine-containing product having the characterizing features of the claims.
The material of the invention comprises polyethylene naphthalate, polytrimethylene naphthalate and/or a liquid crystal polymer, LCP, and has excellent characteristics of oxygen, water, and nicotine impermeability. Due to the temperature ranges the polymers of the invention are favorable to process and will have an acceptable price. The material of the invention is known per se, but its excellent nicotine barrier properties have not been known. Neither has its use for making packages for nicotine-containing products been contemplated.